Enclosing a Porch as a Sunroom

The east-facing open side porch of our New Haven home is 6' x 12'. It's off the kitchen near the separate garage. We love sunrooms and want to enclose the porch with two insulated walls. There'd be three 4 x 6' windows, a window door, and floor and ceiling insulation and finishes. What is a rough cost?

Cassidy ~ New Haven, Connecticut

Cassidy, the easiest way for you to get an accurate cost estimate for your new sunroom is to consult a contractor who works in the New Haven area and has inspected your home and property. Without some detailed drawings and a materials list, it can be difficult to create a project budget and a construction plan. That being said, I can offer you some general guidelines and possible costs for your project.

Site prep and excavation -- If your porch's existing foundation is not adequate enough to support the weight of the new addition, then you may have to start fresh from the ground up. Keep in mind that even if your existing patio is a poured cement slab, that does not necessarily mean that it was designed or built to support the walls of an enclosed porch. Excavating the site and pouring a new cement slab might cost between $1,500 and $3,500, depending on the complexity of the earth work and the dimensions of the slab.

Windows --The windows that you choose for your sunroom will affect not only the overall cost of your project, but also the performance and comfort of the finished space. I recommend double paned windows with Low-E glazing and operable sliding frames. Vinyl framed windows that are 4 feet-by-6 feet might cost you between $350 and $650 a piece, and you can expect to pay quite a bit more money for windows with fiberglass frames or those with wood frames and aluminum cladding. In order to maintain some visual consistency between your house and the new addition, you may want to consider installing new windows that match the style and type of your home's existing ones.

Insulation -- In order for your new sunroom to be comfortable throughout the year, it needs to be well insulated. Two of the most popular insulation choices are spray-in foam, which tends to be the more expensive option, and blown-in fiberglass or cellulose insulation. I like spray-in foam insulation, because it not only seals the space completely, which results in fewer air leaks and less heat loss, but spray-in foam is also a great noise insulator, which helps keep out the racket from neighboring houses and adjacent roadways. You can expect to pay between $750 and $2000 to insulate a small space like this, but the actual cost will be determined by the type of insulation you choose, as well as its overall R-value.

Finishes -- Although there is a wide range of interior finishes for you to choose from, it may be most appropriate to just select a flooring and wall finish that best match your existing home. Tile is a popular choice for sunroom flooring, because tile is able to absorb the sun's heat and is usually not susceptible to fading.

When working with your contractor on the details of your project, it can be helpful if he has some material costs available so that you can select products based on looks and cost. If you don't know any of the costs upfront, then you often find yourself choosing building materials that are too expensive for your budget. Remember, it's a give and take process to come up with the perfect construction plan and still be able to afford to build it. Good luck with your project!